Methods for transmitting digital multimedia and data over the same wires

ABSTRACT

A method of transmitting a data stream over a communication channel, the method comprising: providing symbol sets having different numbers of symbols; modulating data in the data stream that warrant different degrees of protection against noise onto symbols from symbol sets having different numbers of symbols, wherein which symbol set given data in the stream is modulated onto is independent of symbol sets onto which other data in the data stream is modulated onto; and transmitting the symbols.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of application Ser. No. 11/703,080,filed on Feb. 7, 2007, incorporated herein by reference.

BACKGROUND

Today's work and play environments in the home and/or office are repletewith numerous and various devices and appliances, hereinafter referredto generically as appliances, such as home entertainment systems, playstations, computers and surveillance equipment that people use forentertainment and work. The appliances actively interface andcommunicate with their users via video and/or audio displays to provideentertainment and/or to present information that they generate orreceive. Behind the communication interface with human users, theappliances carry on a continuous chatter of digital communication amongthemselves, sending and receiving control, information and entertainmentdata that enable them to maintain the data processing and presentationsthey provide to the users

Various digital communication systems and networks supported bydifferent physical infrastructures and standards for their operationhave been developed to provide the communication needs and demands ofthe appliances and the users who use them. The physical infrastructuresmay comprise coaxial cables, twisted pair cables, phone lines, and/orpower lines and/or may comprise wireless communication channels.However, new appliances and configurations of appliances are constantlyoffering users new features and services that generally require digitalcommunication networks having increased bandwidth. The continual flow ofnew features and services and demand for increased bandwidth havegenerated a “patch work” of different communication systems and networksand standards for managing the systems and networks aimed at satisfyingthe demand.

For example, the development of flat panel LCD digital displaysstimulated the development of digital video interfacing (DVI) utilizingTransition Minimized Differential Signaling (TMDS) technology forhigh-speed transmission of uncompressed serial digital data. Differentcommunication standards defining communication systems incorporating addon features and improvements for transmitting high definition multimediacontent such as high definition video, digital music, digital photos andDVD entertainment from a Source of such content, e.g. a DVD or Set TopBox (STB), to a Sink of the content, such as a TV, material followed.Among the standards are High Definition Multimedia Interface (HDMI),Unified Display Interface (UDI) and DisplayPort.

Whereas the various multimedia communication standards and systemsprovide relatively high data transfer rates, they are generallyconfigured to provide simplex data transmission of multimedia content atrelatively high bit error rates (BER) from a Source of multimediacontent to a Sink of the content over relatively short distances. Thestandards and systems generally require special dedicated connectors andcable assemblies and their transmission is generally limited to a reachof less than about 15 meters. Duplex and half duplex transmission ofcontrol data between a Source and a Sink that the standards require isperformed at relatively low bandwidth of up to 1 Mbps and is generallysupported by a dedicated channel separate from the channel over whichthe simplex multimedia data is transmitted.

The noted multimedia standards and systems do not support high qualityrelatively low BER full duplex data transmission that is generallyrequired by communication networks that support information exchangebetween various appliances, e.g. various computer platforms, in ahousehold or office environment. For example, uncompressed highdefinition video may be streamed from Source to Sink by these systems atdata rates of about a gigabit per second (Gbps) for each of the redgreen and blue (RGB) color channels used to provide video. At theserates, substantial noise and in particular echo and near end cross talk(NEXT) may be generated that interferes with data transmission and toprovide information exchange at an acceptable BER, the exchangedinformation must generally be protected by a relatively large codingoverhead of redundant bits. The increased overhead substantiallyincreases complexity of coding and decoding software and hardwarerequired to process the information and thereby the cost of the systemsif they are configured to support full duplex communication.

Full duplex information exchange between appliances at the home andoffice that are characterized by relatively low BER are typicallyprovided by networks such Ethernet 100 Base-T, WIFI, MOCA HOMEPNA orHOMEPLUG AV. The various Ethernet networks provide duplex informationexchange over twisted pair wires at bandwidths that correspond toratings of the twisted pairs. WIFI provides information exchange overwireless channels. MOCA provides communication over coaxial cable.HOMEPNA and HOMEPLUG AV support in-home networking over copper phonelines and power lines respectively that exist in the home.

The various information exchange networks do not in general providesufficient bandwidth to support transmission of uncompressed multimediacontent, which typically requires data transmission rates of about 1Gbps for each of the R, G and B color channels of a video display. Alatest Ethernet standard 10Gbase-T, while having sufficient bandwidthfor supporting transmission of uncompressed high definition multimediacontent, is not configured to do so. It does not provide multimediaclock regeneration or support for Hot Plug Detection (HPD), ConsumerElectronics Control (CEC) or Display Data Channel (DDC). 10Gbase-Tnetworks are designed to cope with echo, NEXT and alien cross talk(ANEXT) and comprise terminal equipment that implements relativelycomplex echo/cross talk cancellers and support processing relativelylarge error correction overheads. As a result, 10Gbase-T terminalequipment and networks are relatively complicated and expensive.

Since none of the various multimedia communication systems andinformation exchange communication networks provide both satisfactoryuncompressed multimedia transmission and information exchange, home andoffice environments that provide both are equipped with a complex ofdifferent hardware and software systems.

SUMMARY

An aspect of some embodiments of the invention relates to providing asingle flexible format for transmitting different types of data over asame physical communication network. In accordance with an embodiment ofthe invention, data is transmitted over the network in packets ofwaveforms and the uniform flexible format comprises a uniform format forthe packet, hereinafter referred to as a “U-Pac”, for encapsulating datafor transmission over the physical communication network. The differenttypes of data optionally comprise information exchange data such asEthernet data and uncompressed multimedia audiovisual data such as HDMI1.3, DVI 1.0, UDI and/or DisplayPort data.

An aspect of some embodiments of the invention, relates to providingresistance to noise for data transmitted over the same physical networkresponsive to the type of data transmitted and/or a desired degree ofprotection against noise. Different degrees of resistance to noise areprovided by modulating different types of data that warrant differentdegrees of protection against noise onto waveform sets having differentnumbers of waveforms. Optionally, the waveform sets having differentnumbers of waveforms are chosen from waveform sets comprising a largestset having a largest number of waveforms and subsets of the largest set.

According to an aspect of some embodiments of the invention, in a datastream comprising data modulated onto a sequence of waveforms, choice ofa waveform onto which given data is modulated is independent of choicesof waveforms onto which other data in the data stream is modulated. Forexample, in some embodiments of the invention, in a data streamcomprising data modulated onto a sequence of waveforms, temporallyadjacent waveforms are, optionally, chosen from different waveform sets.If data in the data stream is modulated onto and transmitted in waveformpackets, such as a U-Pac, a same waveform packet may contain waveformschosen from different waveform sets.

By way of example, let a waveform set comprising i waveforms chosen fromM waveforms comprised in a largest set of waveforms be represented byS(M,i), where the largest set of waveforms is represented by S(M,M) andi satisfies a relation 0<i≦M. Then, in accordance with an embodiment ofthe invention, if a first type of data is modulated onto a waveform setS(M,i), a second type of data warranting higher resistance to noise thanthe first type of data is modulated for transmission onto a waveform setS(M,j) where j<i. If data is encapsulated in U-Pacs, a same U-Pacoptionally comprises encapsulated data modulated onto different symbolsets to provide different data in the U-Pac with different levels ofprotections against noise. Optionally, the different symbol sets arechosen from a set {S(M,i): 0<i≦M} of symbol sets.

It is noted that choosing waveform sets from a same largest waveform setcan be advantageous in simplifying implementation of a communicationnetwork that transmits data in accordance with an embodiment of theinvention. For example, if all waveforms onto which the data ismodulated are chosen from a same largest waveform set, different slicersdo not have to be used to slice waveforms from different waveform setsand substantially identical slicers may be used in all receivers in thenetwork. The slicers optionally slice and generate error directions forall received waveforms assuming that the waveforms are waveforms in thelargest waveform set, independent of the actual waveform set to which agiven waveform belongs. In accordance with an embodiment of theinvention, demodulation of a given received waveform to a correctwaveform of a waveform set to which the given waveform belongs isperformed using information carried in the data indicating the waveformset to which the given waveform belongs.

Hereinafter, a waveform onto which data is modulated for transmission isalso referred to as a “symbol” and a set of waveforms onto which data ismodulated is also referred to as a “symbol set”. Modulating data ontowaveform sets comprising different numbers of waveforms in accordancewith an embodiment of the invention is referred to as dynamic waveformmodulation (DWM). For convenience alphabetic and/or alphanumericdesignations used to represent symbol sets may also be used inreferencing symbols belonging to the symbol set. For example, thealphabetic symbol set designation S(M,i) may also be used in referencinga symbol belonging to the symbol set S(M,i). Similarly, a designation ofa symbol may be used to designate a symbol set to which the symbolbelongs.

Different types of waveforms, such as for example, frequency shift,phase shift or amplitude shift keyed waveforms, may be used in thepractice of embodiments of the invention. Optionally, a largest waveformset S(M,M) comprises an M-ary pulse-modulation symbol set having M=2^(k)different waveforms. In some embodiments of the invention, thepulse-modulation waveforms are pulse amplitude modulation (PAM) symbols.Optionally, the symbols are pulse-position modulation (PPM) symbols.Optionally, the symbols are pulse-duration modulation (PDM) symbols. Forconvenience of presentation, it is assumed hereinafter that symbols arePAM symbols, a largest set of PAM symbols is represented by P(M,M) and asubset of P(M,M) comprising i PAM symbols is represented by P(M,i).

In some embodiments of the invention, the symbols onto which data ismodulated for transmission are transmitted over a twisted pair (TP)cable optionally comprising four pairs of twisted wires. Optionally,each symbol is a four-dimensional symbol comprising four substantiallysimultaneously transmitted “one dimensional” symbols, each transmittedover a different twisted pair of the TP cable.

Let, a four-dimensional symbol in accordance with an embodiment of theinvention be represented by “S4D”. In accordance with an embodiment ofthe invention, each of the one dimensional symbols that make up a fourdimensional symbol S4D is chosen from a same set of one-dimensionalsymbols S(M,i). The index i is smaller for types of data warrantinghigher noise resistance than for types of data warranting lower noiseprotection. Let a four dimensional symbol comprising one dimensionalsymbols S(M,i) (i.e. symbols chosen from the S(M,i) symbol set) berepresented by “S4D-S(M,i)”. A four dimensional symbol comprising onedimensional PAM symbols P(M)_(i) is represented by “S4D-P(M,i)”.

In some embodiments of the invention, the TP cable is a Cat5e or Cat6unshielded TP (UTP) cable comprising unshielded twisted pairs.Optionally, the TP cable is up to about 100 m in length andfour-dimensional symbols S4D are transmitted over the TP cable at a rateof 250 Msym/s (mega-symbols per second) per TP. Assuming that each onedimensional symbol in a S4D symbol is a PAM(16,16) symbol (i.e. each PAMsymbol is a four bit symbol) each TP transmits data at a rate of about 1Gbps (a gigabit per second) for a total bandwidth of about 4 Gbps. Insome embodiments of the invention, the TP cable is up to about 70 m inlength and S4D symbols are transmitted over the cable at a rate of 500Msym/s per TP for a total bandwidth of about 8 Gbps.

An aspect of some embodiments of the invention relates to providing amethod of reducing noise generated in a communication channel over whichboth uncompressed multimedia data is transmitted from a Source to a Sinkin simplex mode and over which data is exchanged between the Source andthe Sink in full duplex mode.

The inventors have noted that for a communication channel transmittinguncompressed multimedia data in simplex and information data in duplexbetween a Source and Sink, relatively large amounts of noise at the Sinkare due to Echo and Near End Cross Talk (NEXT). In accordance with anembodiment of the invention, to reduce Echo and NEXT, information datafrom the Sink to the Source is transmitted at a lower symbol rate than asymbol rate at which the multimedia data is transmitted from the Sourceto the Sink. Optionally, the Source to Sink multimedia symbol rate isgreater than about 10 times the Source to Sink information symbol rate.Optionally, the multimedia symbol rate is greater than 20 times theSource to Sink information symbol rate. Optionally, the multimediasymbol rate is greater than 30 times the Source to Sink informationsymbol rate. Optionally, the multimedia symbol rate about 40 times theSource to Sink information symbol rate. A network configured to transmitfrom Sink to Source in accordance with an embodiment of the inventioncan substantially reduce NEXT and Echo at the sink and as a result mayenable relatively inexpensive terminal equipment to be used in thenetwork.

There is therefore provided in accordance with an embodiment of theinvention, a method of transmitting a data stream over a communicationchannel, the method comprising: providing symbol sets having differentnumbers of symbols; modulating data in the data stream that warrantdifferent degrees of protection against noise onto symbols from symbolsets having different numbers of symbols, wherein which symbol set givendata in the stream is modulated onto is independent of symbol sets ontowhich other data in the data stream is modulated onto; and transmittingthe symbols.

Optionally, the symbol sets are chosen from symbol sets comprising alargest set having a largest number of symbols and subsets of thelargest set. Additionally or alternatively, the method comprisesconfiguring symbols into packets. Optionally, configuring symbols intopackets comprises configuring symbols from symbol sets having differentnumbers of symbols into a same packet.

In some embodiments of the invention, temporally adjacent symbols arechosen from symbol sets having different numbers of symbols.

In some embodiments of the invention, each symbol is a multidimensionalsymbol comprising a plurality of symbols that are substantiallysimultaneously transmitted over the channel. Optionally, themultidimensional symbol is a four dimensional symbol comprising foursymbols chosen from a same set of symbols.

In some embodiments of the invention, the symbols comprise frequencyshift symbols. In some embodiments of the invention, he symbols comprisephase shift symbols. In some embodiments of the invention, the symbolscomprise amplitude shift symbols. In some embodiments of the invention,the symbols comprise pulse-modulation symbols. In some embodiments ofthe invention, the symbols comprise pulse-position modulation (PPM)symbols. In some embodiments of the invention, the symbols comprisepulse-duration modulation (PDM) symbols. In some embodiments of theinvention, the symbols comprise pulse amplitude modulation (PAM)symbols.

In some embodiments of the invention, the largest set comprises 16symbols.

In some embodiments of the invention the method comprises transmittingthe symbols at a transmission rate up to about 250 Msym/sec. In someembodiments of the invention the method comprises transmitting thesymbols at a transmission rate up to about 500 Msym/sec.

In some embodiments of the invention the method comprises transmittingdata comprises transmitting in simplex mode. Optionally, transmittingdata comprises transmitting in full duplex mode over the channel.Optionally, transmitting in full duplex mode comprises transmitting dataat different rates in different directions over the channel.

There is further provided in accordance with an embodiment of theinvention, a method of transmitting data over a communication channel,the method comprising: transmitting data in simplex mode over thecommunication channel; and transmitting data in full duplex mode atdifferent rates in different directions over the channel.

Alternatively or additionally, transmitting data in full duplex modecomprises transmitting data at a first rate in a direction in which thesimplex data is transmitted and at a second rate lower than the firstrate in a direction opposite the simplex direction.

In some embodiments of the invention, the data comprises TransitionMinimized Differential Signaling (TMDS) data. In some embodiments of theinvention, the data comprises DisplayPort data. In some embodiments ofthe invention, the data comprises uncompressed data. In some embodimentsof the invention, the data comprises multimedia data. Optionally, themultimedia data comprises high definition multimedia data.

In some embodiments of the invention, the method comprises transmittingdata in full duplex mode over the channel. In some embodiments of theinvention, the data comprises Ethernet data.

In some embodiments of the invention, the channel comprises a twistedpair cable. Optionally, the twisted pair cable comprises four twistedpairs. Additionally or alternatively, the twisted pairs are unshielded.In some embodiments of the invention, the twisted pairs are shielded. Insome embodiments of the invention, the cable is a Cat5e cable. In someembodiments of the invention, the cable is a Cat6 cable.

In some embodiments of the invention, simplex and full duplex data aretransmitted over a same twisted pair.

There is further provided in accordance with an embodiment of theinvention, a communication system comprising: a communication channel;and first and second transceivers that communicate with each other overthe channel in simplex and in full duplex mode; wherein data in fullduplex mode is transmitted at different rates in different directionsover the channel.

Optionally, data in full duplex mode is transmitted at a first rate in adirection in which the simplex data is transmitted and at a second ratelower than the first rate in a direction opposite the simplex direction.Additionally or alternatively, the first transceiver transmits data in adata stream to the second transceiver and modulates data in the datastream that warrant different degrees of protection against noise ontosymbols from symbol sets having different numbers of symbols.Optionally, the symbol sets are chosen from symbol sets comprising alargest set having a largest number of symbols and subsets of thelargest set. Optionally, the first transceiver configures symbols intopackets. Optionally, the first transceiver packets symbols from symbolsets having different numbers of symbols into a same packet. In someembodiments of the invention, the first transceiver packets symbols fromsymbol sets having different numbers of symbols temporally adjacent eachother.

In some embodiments of the invention, the data comprises TransitionMinimized Differential Signaling (TMDS) data. In some embodiments of theinvention, the data comprises DisplayPort data. In some embodiments ofthe invention, the data comprises uncompressed data. In some embodimentsof the invention, the data comprises multimedia data. Optionally, themultimedia data comprises high definition multimedia data. In someembodiments of the invention, the data comprises Ethernet data.

In some embodiments of the invention, the channel comprises a twistedpair cable. Optionally, the twisted pair cable comprises four twistedpairs. Additionally or alternatively, the twisted pairs are unshielded.In some embodiments of the invention, the twisted pairs are shielded. Insome embodiments of the invention, the cable is a Cat5e cable. In someembodiments of the invention, the cable is a Cat6 cable. In someembodiments of the invention, simplex and full duplex data aretransmitted over a same twisted pair.

There is further provided in accordance with an embodiment of theinvention, a transceiver comprising: a receiver for receiving datatransmitted over a communication channel; a transmitter for transmittingdata over the communication channel; and circuitry for modulating datafor transmission over the channel by the transmitter that modulates datathat warrant different degrees of protection against noise onto symbolsfrom symbol sets having different numbers of symbols. Optionally, thesymbol sets are chosen from symbol sets comprising a largest set havinga largest number of symbols and subsets of the largest set. Additionallyor alternatively, the circuitry configures symbols into packets. In someembodiments of the invention, the circuitry packets symbols from symbolsets having different numbers of symbols into a same packet. In someembodiments of the invention, the circuitry packets symbols from symbolsets having different numbers of symbols temporally adjacent each other.

BRIEF DESCRIPTION OF FIGURES

Examples illustrative of embodiments of the invention are describedbelow with reference to figures attached hereto. In the figures,identical structures, elements or parts that appear in more than onefigure are generally labeled with a same numeral in all the figures inwhich they appear. Dimensions of components and features shown in thefigures are generally chosen for convenience and clarity of presentationand are not necessarily shown to scale. The figures are listed below.

FIG. 1A schematically illustrates transmitting uncompressed multimediadata and Ethernet data over a channel comprising a UTP cable, inaccordance with an embodiment of the invention;

FIG. 1B schematically shows a U-Pac comprising symbols, in accordancewith an embodiment of the invention.

FIG. 2 schematically illustrates encapsulating Ethernet data in a U-Pacof the form shown in FIG. 1B, in accordance with an embodiment of theinvention; and

FIG. 3 schematically illustrates encoding multimedia TransitionMinimized Differential Signaling (TMDS) data in a U-Pac of the formshown in FIG. 1B, in accordance with an embodiment of the invention.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

FIG. 1 schematically shows first and second transceivers 21 and 31,hereinafter referred to as DWM transceivers 21 and 31, communicatingusing dynamic waveform modulation (DWM) to package data in U-Pacs, inaccordance with an embodiment of the invention.

By way of example, DWM transceiver 21 is coupled to the Ethernet and atleast one Source 51 of high definition uncompressed audiovisual (AV)multimedia data from which DWM transceiver receives data to transmit toa Sink 52 via DWM transceiver 31. Optionally, the DWM transceivers 21and 31 transmit data to each other over an unshielded twisted pair (UTP)cable 40. Optionally, UTP cable 40 is a Cat5e or Cat6 cable comprisingfour twisted pairs, TP41, TP42, TP43 and TP44. The multimedia data isassumed to be Transition Minimized Differential Signaling Audio Visual(TMDS-AV) data.

DWM transceiver 21 optionally comprises signal processing and controlcircuitry 24 for encoding/decoding and modulating/demodulating data itreceives and for each twisted pair TP41, TP42, TP43 and TP44 of UTPcable 40, a transmitter, receiver and hybrid circuit. The varioustransmitters, receivers and hybrid circuits are schematicallyrepresented by a transmitter 25, a receiver 26 and a hybrid circuit 27respectively. Optionally, an RJ45 patch 46 mounted to a wall plate 47couples hybrid circuit 27 to each twisted pair TP41, TP42, TP43 andTP44.

DWM transceiver 31 comprises signal processing and control circuitry 34for encoding/decoding and modulating/demodulating data it receives andfor each twisted pair TP41, TP42, TP43 and TP44 of UTP cable 40, atransmitter, receiver and hybrid circuit. The various transmitters,receivers and hybrid circuits are schematically represented by atransmitter 35, a receiver 36 and a hybrid circuit 37 respectively.Optionally, an RJ45 patch 46 mounted to a wall plate 47 couples hybridcircuit 37 to each twisted pair TP41, TP42, TP43 and TP44.

DWM transceiver 21 receives Ethernet data from the Ethernet and TMDS-AVdata and control data from Source 51 and its processing and controlcircuitry 24 encodes and modulates the data optionally onto symbol (i.e.waveform) sets S4D-S(M,i) of different size responsive to a degree ofresistance to noise that is desired for the data. Circuitry 24 thencontrols transmitter 25 to transmit the symbols in packets, U-Pacs,having a same format. In accordance with an embodiment of the invention,the index i is smaller for data warranting higher noise resistance thanfor data warranting lower noise protection.

DWM transceiver 31 receives the U-Pacs and its processing and controlcircuitry 34 demodulates and decodes the symbols they comprise toun-packetize the data they contain and transmits the data to Sink 52.Whereas TMDS-AV data is transmitted in simplex mode from Source 51 toSink 52, Ethernet and/or control data transmitted from the Sink to theSource in general requires that the Sink provide a response to theSource and Ethernet and control data is transmitted in full duplexbetween the Source and Sink, in accordance with an embodiment of theinvention. Large block arrows 61 schematically represent simplexmultimedia TMDS-AV data and double arrowhead block arrows 62 representfull duplex Ethernet and/or control data.

In responding to Ethernet and control data received from Source 51, Sink52 optionally packetizes its response in U-Pacs using symbol setsS4D-S(M,i) for transmission similarly to the way in which Source 51packetizes its data for transmission. However, the inventors have notedthat transmission of TMDS data and full duplex Ethernet data over a samechannel, such as the twisted pair (TP), hybrid terminated channel shownin FIG. 1A, at high transmission rates required by TMDS data cangenerate substantial amounts of noise in the channel. In particular,echo and near end cross talk (NEXT) generated by near end transmittersmake substantial contributions to the noise. Both the near endtransmitter Echo and Next can exhibit exponential growth with frequencyof signal transmission over a TP channel similar to that shown in FIG.1A. For example, for a 50 m Cat6 cable, noise can increase by as much asabout 30 dB for an increase in frequency of transmission from about 10MHz to about 300 MHz. The inventors have further noted that full duplextransmission of Ethernet does not in general require a same datatransmission rate as transmission of simplex TMDS data. Therefore, insome embodiments of the invention, whereas transceiver 21 is configuredto transmit both TMDS data and full duplex Ethernet and/or control data,at a relatively high transmission rate required by TMDS data,transceiver 31 is configured to transmit Ethernet and/or control data totransceiver 21 at a substantially lower transmission rate. The lowertransmission rate at which transceiver 31 transmits data cansubstantially reduce echo and NEXT at transceiver 31.

In some embodiments of the invention, DWM transceiver 21 transmits TMDSand Ethernet and/or control data to transceiver 31 at a transmissionrate greater than about 10 times the transmission rate at which DWMtransceiver 31 transmits Ethernet and/or control data to transceiver 21.Optionally, DWM transceiver 21 transmits at a transmission rate 20 timesgreater than DWM transceiver 31. Optionally, DWM transceiver 21transmits at a transmission rate 30 times greater than DWM transceiver31. Optionally, DWM transceiver 21 transmits at a transmission rate 40times greater than DWM transceiver 31. For example, in some embodimentsof the invention, DWM transceiver 21 transmits TMDS and Ethernet and/orcontrol data to DWM transceiver 31 at 250 Msym/sec or 500 Msym/sec andDWM transceiver 31 transmits Ethernet and/or control data to transceiver21 at 12.5 Msym/sec.

It is noted that the relatively low transmission rates at which DWMtransceiver 31 transmits data to DWM transceiver 21 can generatesignificant base line wander (BLW) due to transformers that optionallycouple each transceiver to TP cable 40. To reduce possible BLW, DWMtransceiver 31 optionally transmits data using “DC-balanced” waveformsets, i.e. DC-balanced symbol sets. Whereas, any suitable DC-balancedwaveform set and methods of transmitting such waveform sets known in theart may be used by DWM transceiver 31 to transmit data, optionally DWMtransceiver 31 is configured to transmit data using S4D-P(M,i) symbols.

Let a DC-balanced symbol set in accordance with an embodiment of theinvention be represented by “±S4D-P(M,i)”. In accordance with anembodiment of the invention, the set comprises positive and negativevoltage level symbols S4D-P(M,i) and for each positive voltage levelsymbol, the set comprises a “mirror image” negative voltage level symbolhaving a same magnitude as the positive level symbol. Mirror imagesymbols represent identical data and are selectively transmitted by DWMtransceiver 31 so that BLW generated by positive symbols issubstantially neutralized by transmission of negative mirror imagesymbols. In accordance with an embodiment of the invention, DWMtransceiver 31 uses symbols from a data set ±S4D-P(M,i) having a smallervalue of i for data warranting higher noise resistance.

Optionally, the S4D-S(M,i) symbol sets are four dimensional PAM symbolssets S4D-P(M,i) and with each component one-dimension PAM(M,i) symbol ofthe four dimensional S4D-P(M,i) symbol transmitted substantiallysimultaneously over a different one of TP41, TP42, TP43 and TP44. Forconvenience of presentation, it is assumed that the one dimensional PAMsymbols are PAM(16,i) symbols and that i=2^(k) where k is equal to anumber of bits of information represented by a PAM(16,i) and satisfies acondition 1≦k≦4. The index i has a value equal to 16 for the largest PAMset and assumes values 8, 4 or 2 for subsets of the largest set withsymbols in subsets having smaller i and therefore smaller numbers ofsymbols being easier to distinguish one from the other and havingimproved symbol error rate (SER). For values of i equal to 16, 8, 4 and2 each PAM symbol respectively contains 4, 3, 2 and 1 bit ofinformation. Each symbol of the corresponding four-dimensionalS4D-P(M,i) symbol sets contains 16, 12, 8 and 4 bits of information.

It is noted that for each decrease in k by 1, an amplitude differencebetween symbols in a symbol set S4D-P(M,i) is doubled, making it iseasier to differentiate between symbols transmitted between transceiver21 and 31 and improving the signal to mean squared error (MSE) ratio ofslicers in the transceivers used in determining which symbols isreceived by the transceivers. Signal to MSE ratio (MSER) is defined byan expression MSER=(10*log₁₀((d/2)²/E(e²)) where d is a minimal distancebetween slicer decision levels and E(e²) is a mean of the squared slicererror signal at the decision levels. As a result, for each decrease in kby 1, d doubles and the MSER improves by 6 dB. Assuming Additive WhiteGaussian Noise (AWGN), in the channel coupling transceivers 21 and 31,for a given level of noise in the channel, improvement in MSER by 6 dB,substantially improves a symbol error rate (SER) in symbols transmittedbetween the transceivers. For example assuming a SER of 10⁻⁵ a 6 dBimprovement in MSE improves the SER to 10⁻¹⁷ and SERs of 10⁻⁷ and 10⁻⁹are improved to 10⁻²⁵, and 10⁻³² respectively. The inventors havedetermined that the improvement in SER provided by reducing i by 1provides about a same improvement in SER for a AWGN channel as isprovided by encoding data in accordance with a Reed-Solomon (RS) codehaving an error correction capability of up to 3 data symbols.

FIG. 1B schematically shows a U-Pac 100 comprising S4D-P(16,i) symbolsin accordance with an embodiment of the invention. U-Pac 100 comprises aheader section 101, a payload section 102 and a tail section 103.Payload section 102 comprises a plurality of symbols 110 that encode“payload” data to be delivered from one to the other of Source 51 andSink 52 (FIG. 1A). The data in the payload section of U-Pac 100 isencoded and modulated onto S4D-P(16,i) symbols having index i whichdepends upon a level of protection against noise with which it isdesired to protect the data. In accordance with an embodiment of theinvention, different parts of payload 102 may have different values of iand thereby different levels of SER and anti-noise protection. Header101 and tail 103 comprise management data used for processinginformation comprised in the packet and data in the header and tail isencoded and modulated onto S4D-P(16,4) symbols each representing 8 bitsto provide the data with relatively low SER. Optionally, the headercomprises two symbols, a type symbol 112 and a Stream ID symbol 113.Type symbol 112 is optionally configured to characterize up to 64different types, examples of which are discussed below, of U-Pacs.Stream ID comprises data that identifies Source 51 and Sink 52. Tail 103optionally comprises a CRC-8 symbol 114 and an idle symbol 115 thatmarks the end of U-Pac 100.

By way of example, FIG. 2 shows a flow chart 200 schematicallyillustrating encapsulating Ethernet data into a U-Pac 100, in accordancewith an embodiment of the invention.

In a process step 201 a stream of Ethernet data to be transmitted toSink 52 is received by first transceiver 21. A block 202 of eight (8)Ethernet octets in the stream of Ethernet data is schematically shown tothe right of process step 201. In a process step 203 a data/control bitshown shaded is added to the eight (8) Ethernet octets shown in block202 to a form a “64B/65B” code block 204 of sixty-five (65) bits.

In a step 205 twelve sixty-five (65) bit code blocks 204 are aggregatedto form a payload data section 207 that will become with furtherprocessing a payload section of U-Pac 100. A header data section 206 andtail data section 208 are added to the payload section to form anaggregate code block 210. Header data section 206 optionally comprises a“Type” octet that defines the type of data in the aggregate and U-Pac100 as Ethernet data and a Stream ID octet. Tail 208 optionallycomprises a CRC-8 octet. Aggregate code block 210 comprises 768 Ethernetpayload bits and 36 control bits (header and tale bits plus the controlbit added in step 203) for a total of 804 bits. Optionally, the data inaggregate block 210 is scrambled in a step 212 to provide a scrambledaggregate data block S210 having header, payload and tail sections S206,S207 and S208 respectively. In a step 214, the data in scrambled,aggregate code block S210 is mapped onto a set of S4D-P(16,i) symbolsand a symbol is added to tail S208 to generate header 101, payload 102and tail 103 of a U-Pac 100.

In accordance with an embodiment of the invention, data in headersection S206 and tail section S208 of scrambled aggregate S210 is mappedto S4D-P(16,4) symbols, each of which represents 8 bits of data, toprovide the control data with a relatively low SER. Header 101 and tail103 have two (2) S4D-P(16,4) symbols each. The Ethernet data in payloadsection S207 is optionally mapped to S4D-P(16,8) symbols in payload 102,each of which symbols represents 12 bits of data, so that payload 102has sixty-five (65) S4D-P(16,8) symbols. U-Pac 100 therefore comprises atotal of sixty-nine (69) S4D-P(16,i) symbols and comprises 768 bits ofEthernet payload data. Assuming the Ethernet data received by DWMtransceiver 21 is 100 Mbps Ethernet, to support the data transmissionrate the transceiver transmits an Ethernet U-Pac 100 of 69 S4D-P(16,i)symbols to Sink 52 via DWM transceiver 31, in accordance with anembodiment of the invention, every 7.68 μs for a transmission rate ofabout 9 Mega-symbols of Ethernet data per second (Msym/sec). Optionally,Sink 52 (FIG. 1A) responds to the Ethernet information it receives at asame rate, and transmits back to transceiver 21 via transceiver 31 about9 Mega-symbols of Ethernet data per second (Msym/sec). Symboltransmission between DWM transceivers 21 and 31 in accordance with anembodiment of the invention, therefore operates in a full duplex modethat supports 100 Mbps full duplex Ethernet transmission.

FIG. 3 shows a flow chart 300 that schematically illustratesencapsulating TMDS-AV data from a TMDS-AV data stream used forgenerating an audiovisual display into U-Pacs, in accordance with anembodiment of the invention.

A stream of TMDS-AV data comprises three different types of datatransmitted during periods, hereinafter referred to as “TMDS periods” or“T-periods”, having fixed duration “T”. During each TMDS period one ofthe three different types of data is transmitted for each of three TMDSchannels. The types of data are video data (“V” data), control data (“C”data) and data-island packet data (“I” data). During video data periods,also referred to as a “V periods”, each TMDS channel carries pixel colordata encoded in 8 bits, for a total of 24 bits of video data per period.During data island TMDS periods, also referred to as “I periods”, theTMDS channels carry audio data, which may comprise for example audiosamples acquired at 192 kHz for each of 8 audio channels and informationframes, “infoframes”, comprising data that characterizes audio and videodata in the TMDS-AV stream. During an I period each TMDS channel carries4 bits of data so that the three TDMS channels carry a total of 12 bitsof data during the I period. During control data TMDS periods, alsoreferred to as “C periods”, the TMDS channels carry inter aliahorizontal and vertical synchronization data. Each TDMS channeltypically carries 2 bits of control data during a C period for a totalof 6 bits of control data during the period. Sequences of differenttypes of TMDS periods in the TDMS-AV stream are generally separated fromeach other by “guard bands” that are 2 TDMS periods, “G periods”, long.

In a process step 302 in FIG. 3 DWM transceiver 21 receives a TMDS-AVdata stream to be transmitted to Sink 52 via DWM transceiver 31. A datablock 304 of data in the TMDS-AV stream encoding a single horizontalline of video data and accompanying audio data is schematically shownbeing received by the transceiver. The data is assumed, by way ofexample, to be used to generate a progressive video display that isrefreshed at 60 Hz and comprises 1080 active and 45 blank horizontallines, each having 1920 24 bit pixels and 280 blank pixels. The videodisplay is assumed accompanied by eight 8 audio channels sampled at 192kHz to provide 8 level samples. Data block 304 therefore is 2200 TMDSperiods long, of which 1920 periods are video data periods, i.e. Vperiods, during each of which 24 bits of pixel data are transmitted and280 TMDS periods are “blank” TMDS periods. In FIG. 3 a TMDS T-period isgenerically denoted by its duration “T”. Of the 280 blank T-periods afirst 96 T-periods comprise control, C periods, or guard band, G periodseach carrying 6 bits of data, a middle 96 periods comprise data island,I periods each carrying 12 bits encoding audio data and a last 88periods comprise control C or G periods.

In accordance with an embodiment of the invention, in a process block306 each 16 T-periods of TMDS data in data block 304 are encoded intoS4D-P(16,i) symbols, and a header, hereinafter a “sub-packet header”,added to the symbols to form a sub-packet. The sub-packet headeroptionally comprises a S4D-P(16,4) symbol that characterizes the data inthe sub-packet. For example, the sub-packet header optionallydistinguishes between a sub-packet comprising only control data from asub-packet comprising control and guard data or a sub-packet comprisingonly data island data. Sub-packets 310 generated in process step 306from data in data block 304 are schematically shown in a data block 308and are labeled with a letter or letters indicating the type of datathey contain. Sub-packets 310 labeled “C”, “I”, or “V” comprise onlycontrol, data island or video pixel data respectively. “Mixed”sub-packets comprising more than one type of data are labeled by theletters of each of the data types they contain. For example, sub-packets310 in block 308 that contain both control (C) data and guard (G) dataare labeled by both G and C.

In accordance with an embodiment of the invention, V data, is encodedinto S4D-P(16,16) symbols, and I data, C data and G data are encodedinto S4D-P(16,8) symbols. Since each T-period of V data comprises 24bits of data, each V period is encoded to 1.5 S4D-P(16,16) symbols.Similarly, each I data period comprises 12 bits of data and is encodedto 1 S4D-P(16,8) symbol and each C data or G period comprises 6 bits ofdata and is encoded to 0.5 S4D-P(16,8) symbols. With the addition of thesub-packet header comprising one S4D-P(16,4) symbol, each type of V datasub-packet 310 comprises 25 S4D-P(16,16) symbols, each I data sub-packetcomprises 17 S4D-P(16,8) symbols and each C or CG sub-packet 310comprises 9 S4D-P(16,8) symbols. The number of S4D-P(16,i) symbols ineach type of sub-packet 310 in FIG. 3 is shown in parentheses for atleast one of the type of sub-packet below the sub-packet.

In accordance with an embodiment of the invention, V data is alwaysencapsulated in sub-packets 310 comprising only V data in addition tothe sub-packet header. Therefore, if data in a sequence of 16 T-periodsthat is to be encapsulated in a sub-packet includes T-periods havingdata other than V data followed by T-periods having V data, thesub-packet is a “shortened sub-packet” generated only from data in thenon-V data T-periods and includes data in less than 16 T-periods. V datain the remaining T-periods are encapsulated in a next sub-packet. Ashortened sub-packet 310 comprising data from only 8 T-periods isdistinguished by a reference numeral 312.

In a process step 314, sub-packets 310 are encapsulated in U-Pacs 320having a configuration shown for U-Pac 100 (FIG. 1B). U-Pacs 320encapsulating sub-packets 310 generated in process step 314 are shown ina U-Pac data block 330. In accordance with an embodiment of theinvention, each U-Pac 320 typically comprises, 4 sub-packets 310 (datafrom 64 T-periods of data block 304), a U-Pac header 321 comprising twoS4D-P(16,4) symbols and a U-Pac tail 322 comprising two S4D-P(16,4)symbols. Similar to the case of sub-packets 310, optionally, a U-Pac 320does not “mix” sub-packets 310 having V data with sub-packets 310comprising other than V data. In accordance with an embodiment of theinvention, a sub-packet 310 comprising V data is encapsulated in a sameU-Pac 320 only with other sub-packets 310 comprising V data. As aresult, to satisfy the non-mixing constraint, a U-Pac 310 such as forexample a U-Pac 320 distinguished in FIG. 3 by a reference numeral 324,may comprise less than 4 sub-packets 310.

A total of 35 U-Pacs 320, labeled U-Pac 1-U-Pac 35, generated asdescribed above are required to encapsulate all the TMDS data comprisedin data block 304 that defines a single 1080 p 24 bpp+8 L-PCM audiosampled at 192 KHz. Of the 35 U-Pacs 320, 30 U-Pacs comprise pixeldefining D data and 5 U-Pacs comprise control and/or audio data. Sincedifferent sub-packets 310 may comprise different numbers of S4D-P(16,i)symbols and as noted above, different U-Pacs 320 may comprise differentnumbers of sub-packets, different U-Pacs 320 may comprise differentnumbers of S4D-P(16,i) symbols. A number of S4D-P(16,i) symbols in eachU-Pac 320 in U-Pac data block 330 is shown for each U-Pac 320. A totalof 3346 S4D-P(16,i) symbols are used to encapsulate the TMDS data fordata block 304.

In order to support the refresh rate of 60 Hz, DWM transceiver 21 musttransmit 60×1125 lines of 3346 S4D-P(16,i) symbols to DWM transceiver 31every second for a transmission rate of about 226 Msym/sec. In anembodiment of the invention, DWM transceivers 21 and 31 operate attransmission rates of 250 Msym/sec, which readily supports the bandwidthrequired for 226 Msym/sec simplex transmission of TMDS data plus 9Msym/sec full duplex Ethernet transmission noted above between thetransceivers. In an embodiment of the invention, the transceiversoperate at transmission rates of 500 Msym/sec which supportssimultaneous transmission of two TMDS streams plus full duplex Ethernet.

In the description and claims of the application, each of the words“comprise” “include” and “have”, and forms thereof, are not necessarilylimited to members in a list with which the words may be associated.

The invention has been described using various detailed descriptions ofembodiments thereof that are provided by way of example and are notintended to limit the scope of the invention. The described embodimentsmay comprise different features, not all of which are required in allembodiments of the invention. Some embodiments of the invention utilizeonly some of the features or possible combinations of the features.Variations of embodiments of the invention that are described andembodiments of the invention comprising different combinations offeatures noted in the described embodiments will occur to persons withskill in the art. It is intended that the scope of the invention belimited only by the claims and that the claims be interpreted to includeall such variations and combinations.

1. A method comprising: transmitting a packet-based downstreamtransmission of lossless high definition digital video over a firstphysical medium comprising at least one conductive wire; transmitting apacket-based downstream transmission of a bidirectional data channelover a second physical medium comprising at least one conductive wire,wherein the first physical medium and the second physical medium have atleast one common wire; transmitting the upstream transmission of thebidirectional data channel over the common wire; and acceptingpredefined packets that are detected as erroneous; wherein the frequencybands of the upstream and downstream transmissions at least partiallyoverlap.
 2. The method of claim 1, further comprising modulating thedownstream transmission of the lossless high definition digital videowith a first modulation providing a first level of protection againstnoise; and modulating the downstream transmission of the bidirectionaldata channel with a second modulation providing a second level ofprotection against noise.
 3. The method of claim 2, wherein the firstand the second modulations are pulse amplitude modulations.
 4. Themethod of claim 2, wherein the first and the second modulations use atleast partially overlapping subsets of the same symbol set.
 5. Themethod of claim 2, further comprising the step of receiving the packetsof the downstream transmissions of the lossless high definition digitalvideo and the bidirectional data channel, and mapping the receivedpackets to the appropriate modulators.
 6. The method of claim 5, whereinthe different modulations use subsets of the same symbol set.
 7. Themethod of claim 1, wherein the predefined packets are packets comprisingvideo pixel data.
 8. The method of claim 1, further comprising the stepof transmitting packets containing predefined data types without anerror indication overhead.
 9. The method of claim 1, further comprisingthe step of multiplexing the various downstream transmissions before thestep of transmitting the downstream transmissions.
 10. A methodcomprising: multiplexing a first data stream and lossless highdefinition pixel data; transmitting the multiplexed result over a set ofwires utilizing a first frequency band; and receiving a second datastream, wherein the second data stream is received over at least asubset of the wires utilized for the multiplexed transmission, and thereceived data stream utilizes a second frequency band that at leastpartially overlaps with the first frequency band; wherein the methoddoes not include a step of discarding a portion of the pixel data, evenupon receiving an indication that the portion of the pixel data containsan erroneous data bit; and the method further comprising transmittingvideo clock related data and video synchronization data.
 11. The methodof claim 10, further comprising modulating some of the symbols of themultiplexed result with a first modulation providing a first level ofprotection against noise, and some of the symbols of the multiplexedresult with a second modulation providing a second level of protectionagainst noise.
 12. The method of claim 11, wherein the first and thesecond modulations are pulse amplitude modulations.
 13. The method ofclaim 11, wherein the modulation is determined according to the symbol'sdata type.
 14. The method of claim 11, wherein the first and the secondmodulations use at least partially overlapping subsets of the samesymbol set.
 15. The method of claim 14, wherein the symbol set isPAM-16.
 16. The method of claim 11, further comprising the step ofreceiving the multiplexed result and mapping the symbols comprised inthe multiplexed result to the appropriate demodulators.
 17. The methodof claim 10, wherein the lossless high definition pixel data isuncompressed high definition pixel data.
 18. The method of claim 10,further comprising transmitting the multiplexed result using rate thatis independent of the pixel data rate.
 19. The method of claim 10,further comprising transmitting the multiplexed result using rate thatdepends on the pixel data rate.
 20. The method of claim 10, furthercomprising transmitting the clock of the lossless high definition pixeldata.
 21. The method of claim 10, wherein the transmissions are halfduplex.
 22. The method of claim 21, further comprising transmitting thesecond data stream during blanking periods of the lossless highdefinition digital video.
 23. The method of claim 10, wherein thetransmissions are full duplex.
 24. The method of claim 10, wherein thevideo clock related data is the video clock, which is transmitted atleast occasionally.
 25. A method comprising: multiplexing a first datastream and a digital video clock; transmitting the multiplexed resultover a set of wires utilizing a first frequency band; and receiving asecond data stream, wherein the second data stream is received over atleast a subset of the wires utilized for the multiplexed transmission,and the received data stream utilizes a second frequency band that atleast partially overlaps with the first frequency band; the methodfurther comprising transmitting video pixel data and videosynchronization data.
 26. The method of claim 25, further comprisingmodulating the multiplexed first data stream with a first modulationproviding a first level of protection against noise, and modulating themultiplexed digital video clock with a second modulation providing asecond level of protection against noise.
 27. The method of claim 26,wherein the first and the second modulations are pulse amplitudemodulations.
 28. The method of claim 26, wherein the first and thesecond modulations use at least partially overlapping subsets of thesame symbol set.
 29. The method of claim 28, wherein the symbol set isPAM-16.
 30. The method of claim 25, wherein the digital video clock is avideo clock of uncompressed high definition pixel data.
 31. The methodof claim 25, further comprising transmitting the multiplexed resultusing rate that is independent of the digital video clock.
 32. Themethod of claim 25, further comprising transmitting the multiplexedresult using rate that depends on the digital video clock.
 33. Themethod of claim 32, wherein the digital video clock is transmittedoccasionally.
 34. The method of claim 25, wherein the transmissions arehalf duplex.
 35. The method of claim 34, further comprising transmittingthe second data stream during blanking periods of the video.
 36. Themethod of claim 25, wherein the transmissions are full duplex.